Grip pulley



- G. J. RACKHAM GRIP PULLEY Filed June 17. 1922 2 Sheets-Sheetl Patented Jan. R5, 1924..

UEFETEW STATES FATENT @FFHQE.

GEORGE JOHN RACKHAM, OF'JPUTNEY, LONDON, ENGLAND, ASSIGNOR T ROAIDLESS PATENTS HOLDING COMPANY, 0F WASHINGTON, DISTRICT fiF fiflLU MBllA, A COR- PORATION 0F DELAWARE.

GRIP PULLEY.

Application filed June 17, 1922. Serial No. 568,895.

Toall whom it may concern:

Be it known that I, GEORGE JOHN RACK- HAM, a subject of the King of Great Britain, residing at Putney, London, England, have invented certain new and useful Improvements in Grip Pulleys, of which the following is a specification.

This invention relates to belt pulleys of the kind in which provision is made for firmly gripping the belt with which the pulley is associated when there is a tendency for the latter to slip on the former or where the pulley runs ahead of the belt, and the object of the invention is to provide improved means whereby when the belt starts to slip it will be automatically gripped and carried forward without appreciable lost motion.

Briefly stated, the invention consists in providing the peripheral portion of the pulley with a gripping member which normally engages a rib, flange or series of teeth on the inside of the-belt and normally revolves coincidentally therewith and with other parts of the pulley, but which when the belt slips is retarded and is caused, by devices with which it is associated, to quickly and firmly grip the belt so that the normal relation of the belt and pulley is immediately restored.

More specifically the invention consists in providing a,pulley body which is keyed to a centrally arranged axle and which is provided in its peripheral portion with a flange 35 engaging the belt on one side of the centrally arranged rib or flange of the belt and which is provided also with another portlon or section which engages the belt on the opposite side of the belt rib. This last mentioned section of the pulley is detachably connected with the body of the pulley and this detachable section supports a series of pivotally mounted cams, which engage an annular recessed rail secured to the gripping 45 member, the arrangement being such that when the gripping member is moved'circumferentially relatively to the remainder of the pulley, or the other parts of the pulley run ahead of the gripping member, said gripping member is given a lateral movement which "causes it to. grip the belt in the manner before described. Preferably the gripping member is held yieldingly in engagement with the rib of the belt by springs arranged at intervals around the pulley.

In a modified construction, the pivoted cams are replaced by rollers which engage an annular rail carried by the gripping member and formed with cammed recesses into which the inner ends of the rollers extend.

In the accompanying drawings Figure 1 is a side elevation of a portion of a belt pulley withmy improvements'applied.

Figure 2 is a sectional view thereof.

Figure 3 shows a section of a portion of the pulley on the line 33 of Figure 2.

Figures 4 and 5 are on an enlarged scale.

Figure 4: is a sectional View showing a modified way of operating the gripping member.

Figure 5 shows a section of the pulley on the line 55 of Figure 4.

Referring to Figures 1, 2 and 3, an axle to which the pulley is secured is indicated at A, and B indicates ball hearings in which the axle is supported. The pulley hub C is secured to the axle in any suitable way. The web or body D of the pulley is preferably of the form shown, having an inner part d secured to the hub flange 0, an inclined part d, a straight part 0?, an outwardly inclined part at, and a flange d concentric with the axis of the pulley. The outer edge of the flange d is preferably formed with a bead d5 The pulley is associated with a belt E having on its inner side a rib or flange e which may be continuous or divided: into a series of teeth. Preferably the rib is tapered as shown and one side of the rib is engaged by the inclined part d of the pulley. The inner side of the belt on the opposite side of the rib is engaged by a pulley member F, the outer portion f of which is concentric with the axis of the pulley and is annular or continuous. The web f extends inwardly from the part 7 and is spaced some distance from the rib e of the belt. The part 7? is continuous and concentric with the axis of the pulley and the part i is detachably connected by bolts m to the part d of the pulley section D. The member F is made detachable in order that other parts of the pulley may be properly assembled.

A gripping member G is interposed between the sections F and D. This member is preferably Z-shaped in cross-section. Its lower portion 9 is adapted to engage the inner edge of the rib e, and the inclined side g is adapted to engage one The upper bent edge 9 of this member enters a recess 9 in the member F. This is the preferred construction; The gripping' member G is held in contact with the rib a of the belt by springs H. Any desired number of springs may be employed, the oppois carried forward by the 0 the-member G site ends of each spring being seated in re-- cesses h and h in the members F and G as shown in Figure 3.

An annular rail K concentric with the axis of the pulley is secured, as by welding, and this rail is formed with recesses k to receive 'the inner portions of cams M extending through openings in the member F and pivoted at m to arms N extending outwards from the member F. The cams v shown are of triangular shape al-' though this form of cam is not essential. As indicated in Figure 3, each cam enters a recess 76 in the rail K and i is apparent that if the member G be moved :circumferentially relatively to the member F, the cams are turned and a lateral movement is imparted to the gripping member. Therefore, if, in the operation of the mechanism, the belt starts to sli on the pulley or the pulley runs ahead of the belt the rotary movement of the gripping member G will be retarded while the other portions of the pulley continue to rotate at the normal speed. This relative movement of the pulley members causes the lateral movement of the gripping member and in this way the belt is firmly connected with the pulley by an instantane that there is practically no I one operation so lost motion.

It will be observed that normally the belt ulley by reason of the contact of the parts F and d with the inside of the belt, while the gripping member G is carried around with the o her parts by reason of itscontact with the rib e of the belt, and this member G also serves to carry the belt forward in the normal operation of the pulley, but Said member G :as before stated is capable of a relative circumferential movement independent of the movement of the other parts of the pulley and in this. way the ripping action is performed as just describe I have shown myimprovements applied A to a pulley assoclated with a belt which may be made of rubber or rubber and canvas, such as may be used on a. tractor or similar side of the rib.

.axes of the bolts T, but they may 'trically arranged for purposes of adjustare similarly lettered. In this case, however,

while the essential features of theinvention are the same, details of construction are somewhat different. The hub C of the pulley has secured to it a web 0 which is formed at its outer end with an annular peripheral portion 0' which extends concentricall around the axis of the pulley. To the web is secured by bolts 10 a section P which has an inclined portion 31 adapted to engage the rib e of the belt and a part 10 adapted to engage the under side of the belt on one side of th rib. This part 12 is also preferably formed with a bead {2 The under side of the belt on the opposite side of the rib e is engaged by a detachable pulley section Q which is supported on the peripheral flange 0 of the section 0 Between the section Q, and he rib e of the belt is interposed the gripping member G similar to the gripping member shown in Figures 1, 2 and 3. This gripping member G carries a rail R which is continuous and surrounds the axis of the pulley. It is formed with recesses 9" having wall as indicated in Figure 5. The flange,

0 of the member 0 sup orts rollers S which enter the recesses 1" of the rail B. These rollers may be su ported in various ways. As shown, the ro lers rest on the flange 0 and are provided with bushing 8 through which extend bolts T which are threaded at tand en 'age, in threaded sockets in the member As shown, the rollers S are mounted .toturn concentrically about the be eccen ment. The gripping member G is normally pressed toward or into contact with the rib of the belt by springs V mounted in the manner most clearly indicated in Figure 5,

one end of the spring entering a housing w and the'inner end of the spring being supported on a knob w..

Any suitable number p of such springs arranged around the axis of the pulley may be employed. The action 0 the mechanism is similar to that shown in Figures 1, 2 and 3 and need not be specifica y described further than to say that when the belt starts to slip on the main sections of the pulley, the gripping section, which at times moves circumferentially rela-' tively to the other section is also given a lateral 'movementjo cause the gripping action which compels the belt to quickl adhere to the pulley and with but little ost motion continue the normal operation.

I claim as my invention 1. A grip pulley adapted with a belt having a rib or flange on its innor aide, comprising sections engaging the to be associated inner side of the belt oniopposite sides of the rib and a gripping member interposed between .the pulley sections, and engaging the rib of the belt and being associated with devices which automatically cause it to firmly grasp the ribbed part of the belt when the belt starts to slip on the pulley.

2. A grip pulley adapted to be associated with a belt having a rib or flange on its inner side, comprising pulley sections adapted to engage the under side of the belt on opposite s1 es of the rib, a gripping member inter pose-d between said sections and adapted to engage the rib, means for normally holding the gripping member in engagement with said rib, and devices operating upon said gripping member to move it laterally rela- 1 tively to the pulley sections into firm engagement with the rib when the belt startsto slip.

3. A grip pulley adapted to be associated with a belt having a rib or flange on its inner side, comprising two section mounted to revolve with a centrally arranged axle and havinw outer portions engagin the inside of the belt on opposite sides of tie rib, a gripping member movable relatively to' the pulley sections both circumferentially and engage the inner side of the belt on opposite sides of the rib, a gripping member nterposed between the pulley sections, devices f or yieldingly pressin the gripping member into engagement wit the rib, a rece$ed rail carried by the gripping member,

range site sides of the rib, a Z-shaped gripping and pivotally mounted devices carried by one of the pulley sections and which enter the recesses of the rib whereby when the belt starts to slip on the pulley a gripping action is performed by the gripping member. 5. A grip member interposed between the pulley sections and yieldingly held in engagement with the rib of the belt and having portions en agin the under side of the belt, one si e oft e rib and the inner. face of the rib, and devices associated with the gripping member. for causing it to firmly engage the rib when the'belt slips on the .pulley or the pulley runs ahead of the belt.

6. .A grip pulley adapted to be associated with a belt having a rib or flange on its inner side, comprising two opposed sec-' tions, and a ripping member interposed between the pu le'y sections, and engaging the rib of the belt and being associated with devices Which automatically cause it to firmly pulley ada ted be associated l: with a belt having a ri or fl e on its ingrip the ribbed part of the belt when the belt starts to sli on the pulley.

7, A ul ey adapted to be associated with-a e t raving a rili or flan e on its inner' side, comprising two oppose sections, a gripping member interposed between said sections and ada means fornorm 1y holding the gri pin member in engagement wit said ri an said meansoperatingv u on-said ipping member to move it latera ly relative y to the pulley sections into firm engagement with the rib when the belt starts to slip.

ted to engage the rib,

In testimony whereof, I have hereunto subscribed my name. GEORGE JOHN RAOKHAM- 

